The present invention relates to an arrangement for raising and lowering a floating offshore platform which is provided with legs movable relatively to it and supported, in the operating condition, on the bottom of the sea or on a substructure lowered to the bottom of the sea.
In order to establish the working position of such offshore platforms forming artificial islands, the legs are lowered to the bottom of the sea and the platform is then raised out of the water on the firmly seated legs until the necessary height above sea level has been reached. Lowering the legs onto the substructure is always a critical operation which, unless special measures are taken, can only be carried out under favorable weather conditions. Under favorable sea conditions the platform oscillating up and down with the waves may several times impinge upon the substructure with the extending legs before it is finally fixed. This may cause considerable damage.
The present invention pursues the object of improving equipment of the prior art, so that also under favorable sea conditions, the legs may touch down without shocks or substantially without shocks.
Another object of the present invention is to provide an arrangement of the foregoing character, which is simple in design and construction and which may be economically fabricated.
A further object of the present invention is to provide an arrangement, as described, which is provided with safety devices and which may be readily maintained in service.